diff --git a/uncloud_pay/tests.py b/uncloud_pay/tests.py
index 6a59531..0ee5abc 100644
--- a/uncloud_pay/tests.py
+++ b/uncloud_pay/tests.py
@@ -352,7 +352,6 @@ class BillTestCase(TestCase):
 
 
 class ModifyProductTestCase(TestCase):
-
     def setUp(self):
         self.user = get_user_model().objects.create(
             username='random_user',
@@ -366,12 +365,35 @@ class ModifyProductTestCase(TestCase):
             postal_code="somewhere else",
             active=True)
 
-    def test_modify_recurring_product(self):
+    def test_no_pro_rata_first_bill(self):
+        """
+        The bill should NOT contain a partial amount
         """
 
-        """
+        price = 5
+
+        # Standard 30d recurring product
+        product = SampleRecurringProduct.objects.create(owner=self.user,
+                                                        rc_price=price)
+
+        starting_date = timezone.make_aware(datetime.datetime(2020,3,3))
+        ending_date   = timezone.make_aware(datetime.datetime(2020,3,31))
+        time_diff     = (ending_date - starting_date).total_seconds()
+
+        product.create_order_at(starting_date)
+
+        bills = Bill.create_next_bills_for_user(self.user,
+                                                ending_date=ending_date)
+
+
+        # We expect 1 bill for 1 billing address and 1 time frame
+        self.assertEqual(len(bills), 1)
+
+        pro_rata_amount = time_diff / product.default_recurring_period.value
+
+        self.assertNotEqual(bills[0].sum, pro_rata_amount * price)
+        self.assertEqual(bills[0].sum, price)
 
-        product = SampleRecurringProduct.objects.create(owner=self.user)
 
 
 
@@ -500,111 +522,3 @@ class ModifyProductTestCase(TestCase):
 #         self.assertEqual(len(second_month_bills), 1)
 #         self.assertEqual(float(second_month_bills[0].amount),
 #                 round(12 * recurring_price, AMOUNT_DECIMALS))
-
-# class ProductActivationTestCase(TestCase):
-#     def setUp(self):
-#         self.user = get_user_model().objects.create(
-#                 username='jdoe',
-#                 email='john.doe@domain.tld')
-
-#         self.billing_address = BillingAddress.objects.create(
-#                 owner=self.user,
-#                 street="unknown",
-#                 city="unknown",
-#                 postal_code="unknown")
-
-#     def test_product_activation(self):
-#         starting_date = datetime.fromisoformat('2020-03-01')
-#         one_time_price = 0
-#         recurring_price = 1
-#         description = "Test Product"
-
-#         order = Order.objects.create(
-#                 owner=self.user,
-#                 starting_date=starting_date,
-#                 recurring_period=RecurringPeriod.PER_30D,
-#                 recurring_price=recurring_price,
-#                 one_time_price=one_time_price,
-#                 description=description,
-#                 billing_address=self.billing_address)
-
-#         product = GenericServiceProduct(
-#                 custom_description=description,
-#                 custom_one_time_price=one_time_price,
-#                 custom_recurring_price=recurring_price,
-#                 owner=self.user,
-#                 order=order)
-#         product.save()
-
-#         # Validate initial state: must be awaiting payment.
-#         self.assertEqual(product.status, UncloudStatus.AWAITING_PAYMENT)
-
-#         # Pay initial bill, check that product is activated.
-#         order.generate_initial_bill()
-#         amount = product.order.bills[0].amount
-#         payment = Payment(owner=self.user, amount=amount)
-#         payment.save()
-#         self.assertEqual(
-#                 GenericServiceProduct.objects.get(uuid=product.uuid).status,
-#                 UncloudStatus.PENDING
-#                 )
-
-# class BillingAddressTestCase(TestCase):
-#     def setUp(self):
-#         self.user = get_user_model().objects.create(
-#                 username='jdoe',
-#                 email='john.doe@domain.tld')
-
-#         self.billing_address_01 = BillingAddress.objects.create(
-#                 owner=self.user,
-#                 street="unknown1",
-#                 city="unknown1",
-#                 postal_code="unknown1",
-#                 country="CH")
-
-#         self.billing_address_02 = BillingAddress.objects.create(
-#                 owner=self.user,
-#                 street="unknown2",
-#                 city="unknown2",
-#                 postal_code="unknown2",
-#                 country="CH")
-
-#     def test_billing_with_single_address(self):
-#         # Create new orders somewhere in the past so that we do not encounter
-#         # auto-created initial bills.
-#         starting_date = datetime.fromisoformat('2020-03-01')
-
-#         order_01 = Order.objects.create(
-#                 owner=self.user,
-#                 starting_date=starting_date,
-#                 recurring_period=RecurringPeriod.PER_30D,
-#                 billing_address=self.billing_address_01)
-#         order_02 = Order.objects.create(
-#                 owner=self.user,
-#                 starting_date=starting_date,
-#                 recurring_period=RecurringPeriod.PER_30D,
-#                 billing_address=self.billing_address_01)
-
-#         # We need a single bill since we work with a single address.
-#         bills = Bill.generate_for(2020, 4, self.user)
-#         self.assertEqual(len(bills), 1)
-
-#     def test_billing_with_multiple_addresses(self):
-#         # Create new orders somewhere in the past so that we do not encounter
-#         # auto-created initial bills.
-#         starting_date = datetime.fromisoformat('2020-03-01')
-
-#         order_01 = Order.objects.create(
-#                 owner=self.user,
-#                 starting_date=starting_date,
-#                 recurring_period=RecurringPeriod.PER_30D,
-#                 billing_address=self.billing_address_01)
-#         order_02 = Order.objects.create(
-#                 owner=self.user,
-#                 starting_date=starting_date,
-#                 recurring_period=RecurringPeriod.PER_30D,
-#                 billing_address=self.billing_address_02)
-
-#         # We need different bills since we work with different addresses.
-#         bills = Bill.generate_for(2020, 4, self.user)
-#         self.assertEqual(len(bills), 2)